it's best to get in touch via the developers mailing list - most of the Qt stuff is fairly recent work, and as such likely to be "work in progress".Thus, your best chance of getting such issues fixed is to report them in a timely manner using the appropriate channels - i.e. the devel mailing list or the issue tracker.

It's probably not your fault - according to the archives, there were a number of Qt related issues reported recently, and that's in line with some of the Qt related announcements and commits made recently.Speaking in general, Qt5 is however intended to remain optional - so if you can live without the launcher/QtQuick UI, you could try building with Qt disabled - that is, if you cannot get this solved obviously.